Many different types of analog-to-digital converters (ADCs) are known such as direct conversion ADCs, successive-approximation ADCs, ramp-compare ADCs (e.g., single slope ADC), integrating ADCs (e.g., dual slope ADC) to name but a few. However, all common ADCs are designed to convert analog voltage values into corresponding digital values. When current values are to be digitized the current whose value is sought is supplied to a resistor of a well defined resistance resulting in a respective voltage drop across the resistor equal to the product of the sought current and the resistance. The voltage drop is then digitized by an ADC. One consequence of the above-described current measuring approach is that the resistance value of the resistor is introduced into the measurement results. Thus, systematic errors are introduced in the measurement result when the actual resistance deviates from its desired nominal value which is always the case as the resistance value is subject to unavoidable production tolerances.
Thus, there is a general need for improved analog-to-digital converters which are designed to convert current values and which provide digital measurement values.